Etude electrochimique de radicaux libres—III etude des radicaux derives des naphthyridines −1.5, −1.6, −1.7, −1.8, −2.6 et −2.7 et du bipyridyl-4,4′

In acid medium 1.7, 2.6 and 2.7 naphthyridines gives two 1 F polarographic waves. For certain pH values, the first reduction stage leads to a cation radical B relatively stable for the 1.7 and 2.6 derivatives; in the case of 2.7 naphthyridine, its half life is on the contrary shorter than a few msec. The 1.7 and 2.6 cation radicals disappear by a first order acid and based catalysed reaction leading to a dimer. The mechanism, which is valid for other heterocycles with two nitrogen, is the following: the cation radical B which is formed initially is symmetrical and stable. A hydrogen shift from a nitrogen to a carbon atom leads to a radical C, which is unstable and reacts with B to yield a dimer.